↑A History of China, Dr John A.G. Roberts, Palgrave Macmillan, 2011, ISBN 978-0-230-34536-2, ... period is divided into the Western Zhou, from 1122 to 771 BCE, and the Eastern Zhou, the latter age being further subdivided into the Spring and Autumn period, from 771 to 481 BCE, and the Warring States period, from 481 to 221 BCE ...